Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl
Electroosmosis reduces the available energy from ion transport arising due to concentration gradients across ion-exchange membranes. This work builds on previous efforts to describe the electroosmosis, the permselectivity and the apparent transport number of a membrane, and we show new measurements...
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2025-01-01
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| author | Simon B. B. Solberg Zelalem B. Deress Marte H. Hvamstad Odne S. Burheim |
| author_facet | Simon B. B. Solberg Zelalem B. Deress Marte H. Hvamstad Odne S. Burheim |
| author_sort | Simon B. B. Solberg |
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| description | Electroosmosis reduces the available energy from ion transport arising due to concentration gradients across ion-exchange membranes. This work builds on previous efforts to describe the electroosmosis, the permselectivity and the apparent transport number of a membrane, and we show new measurements of concentration cells with the Selemion CMVN cation-exchange membrane and single-salt solutions of HCl, LiCl, NaCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl. Ionic transport numbers and electroosmotic water transport relative to the membrane are efficiently obtained from a relatively new permselectivity analysis method. We find that the membrane can be described as perfectly selective towards the migration of the cation, and that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>Cl</mi><mo>−</mo></msup></mrow></semantics></math></inline-formula> does not contribute to the net electric current. For the investigated salts, we obtained water transference coefficients, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>t</mi><mi>w</mi></msub></semantics></math></inline-formula>, of 1.1 ± 0.8 for HCl, 9.2 ± 0.8 for LiCl, 4.9 ± 0.2 for NaCl, 3.7 ± 0.4 for KCl, 8.5 ± 0.5 for MgCl<sub>2</sub>, 6.2 ± 0.6 for CaCl<sub>2</sub> and 3.8 ± 0.5 for NH<sub>4</sub>Cl. However, as the test compartment concentrations of LiCl, MgCl<sub>2</sub> and CaCl<sub>2</sub> increased past 3.5, 1.3 and 1.4 mol kg<sup>−1</sup>, respectively, the water transference coefficients appeared to decrease. The presented methods are generally useful for characterising concentration polarisation phenomena in electrochemistry, and may aid in the design of more efficient electrochemical cells. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-09592f3ff6334f239eafd5f2a6b93cf82025-01-24T13:31:54ZengMDPI AGEntropy1099-43002025-01-012717510.3390/e27010075Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>ClSimon B. B. Solberg0Zelalem B. Deress1Marte H. Hvamstad2Odne S. Burheim3Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, NorwayDepartment of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, NorwayDepartment of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, NorwayDepartment of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, NorwayElectroosmosis reduces the available energy from ion transport arising due to concentration gradients across ion-exchange membranes. This work builds on previous efforts to describe the electroosmosis, the permselectivity and the apparent transport number of a membrane, and we show new measurements of concentration cells with the Selemion CMVN cation-exchange membrane and single-salt solutions of HCl, LiCl, NaCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl. Ionic transport numbers and electroosmotic water transport relative to the membrane are efficiently obtained from a relatively new permselectivity analysis method. We find that the membrane can be described as perfectly selective towards the migration of the cation, and that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>Cl</mi><mo>−</mo></msup></mrow></semantics></math></inline-formula> does not contribute to the net electric current. For the investigated salts, we obtained water transference coefficients, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>t</mi><mi>w</mi></msub></semantics></math></inline-formula>, of 1.1 ± 0.8 for HCl, 9.2 ± 0.8 for LiCl, 4.9 ± 0.2 for NaCl, 3.7 ± 0.4 for KCl, 8.5 ± 0.5 for MgCl<sub>2</sub>, 6.2 ± 0.6 for CaCl<sub>2</sub> and 3.8 ± 0.5 for NH<sub>4</sub>Cl. However, as the test compartment concentrations of LiCl, MgCl<sub>2</sub> and CaCl<sub>2</sub> increased past 3.5, 1.3 and 1.4 mol kg<sup>−1</sup>, respectively, the water transference coefficients appeared to decrease. The presented methods are generally useful for characterising concentration polarisation phenomena in electrochemistry, and may aid in the design of more efficient electrochemical cells.https://www.mdpi.com/1099-4300/27/1/75ion-exchange membraneelectrodialysispermselectivityelectroosmosistransport number |
| spellingShingle | Simon B. B. Solberg Zelalem B. Deress Marte H. Hvamstad Odne S. Burheim Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl Entropy ion-exchange membrane electrodialysis permselectivity electroosmosis transport number |
| title | Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl |
| title_full | Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl |
| title_fullStr | Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl |
| title_full_unstemmed | Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl |
| title_short | Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl<sub>2</sub>, CaCl<sub>2</sub> and NH<sub>4</sub>Cl |
| title_sort | transport numbers and electroosmosis in cation exchange membranes with aqueous electrolyte solutions of hcl licl nacl kcl mgcl sub 2 sub cacl sub 2 sub and nh sub 4 sub cl |
| topic | ion-exchange membrane electrodialysis permselectivity electroosmosis transport number |
| url | https://www.mdpi.com/1099-4300/27/1/75 |
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